Dragging map is extremely slow when large GPX file is loaded

[lonvia]

Dragging the map has become almost impossible as soon as a large GPX file is loaded. (The file in question is about 9MB large.) For each move it takes one or two seconds to redraw the map.

In version r4487, dragging still works fine. Once the map is grabbed, it follows the mouse more or less immediately.

[Don-vip]

Could you attach a zip of your file, please ?

[lonvia]

I added the GPX file, but any large GPX file shows the slow down. I just tried downloading the GPX points of downtown Zurich (around 50.000 points) and get the same behaviour.

This is on a Netbook (Linux, 2GB RAM, josm started with -Xmx1024m), so it might be that this slow down is less visible on a larger machine.